Digital images of a document captured by an imaging device may exhibit certain defects in image quality. Consider, for example, a camera-based imaging device used to capture images of book pages. A camera can advantageously capture images of book pages without destroying the book by removing its pages, as would otherwise be done in order to sheet-feed the individual pages into an image scanner. However, the images captured by a camera may be unevenly illuminated by the light source, and may exhibit a color cast (color shift) if the color temperature of the light source does not match that expected by the camera. Furthermore, while the background of printed pages is generally expected to be uniformly white in color, the paper of an older book, as well as older non-book document sheets, may be discolored due to aging effects, causing a further color cast in the captured images.